Recently, emphasized attention has been directed to a solar cell as energy supplying means, instead of petroleum as an energy source tending to generate carbon dioxide leading to global warming. Demands for solar cells have also been increased, in a manner to demand stable supply and decreased costs of various members for constituting a solar cell module to be included in a solar cell. Further, demand has also been enhanced, for improvement of a power generation efficiency of the solar cell.
The solar cell module is configured: to include numerous plate-like solar cell elements arranged to be mutually serially or parallelly wired; and to be packaged into a unit so as to protect the elements. Further, such a solar cell module is typically structured to have a surface on which a solar light impinges and which is covered by a glass plate, in an exemplary manner that gaps of solar cell elements are filled with a composition containing an ethylene vinyl acetate copolymer or the like which is high in transparency and excellent in moisture resistance to thereby form a filling unit; and then a back surface (a lower surface of the filling unit) is sealed with a backside protective film for solar cell.
In case of arranging a solar cell having a solar cell module on a roof of a house or the like, it is preferable for the solar cell to be colored in a dark color such as black from a viewpoint of external appearance, and as such, backside protective films for solar cell colored in a dark color have been brought to be used.
Known examples of a film colored in a dark color include: a sheet consisting of a low heat-storage thermoplastic resin composition containing a thermoplastic resin and an inorganic pigment having an infrared reflective property (See Patent Document 1); and a sheet provided, at its surface, with a black resin layer containing a perylene-based pigment in a manner to reflect a near-infrared light by exhibiting a reflectivity of 30% or more to a light at a wavelength ranging from 800 to 1,100 nm, thereby preventing heat storage therein (See Patent Document 2).
Further known is a laminated body including: a thermoplastic resin layer having a higher heat resistance; an infrared transmissible colored resin layer which is arranged on one side of the thermoplastic resin layer; and a colored resin layer having a higher reflectivity to light which is arranged at the other side of the thermoplastic resin layer (See Patent Document 3).